21580241 has 4 divisors (see below), whose sum is σ = 21709632. Its totient is φ = 21450852.

The previous prime is 21580217. The next prime is 21580243. The reversal of 21580241 is 14208512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21580241 - 2²² = 17385937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21580243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64445 + ... + 64778.

It is an arithmetic number, because the mean of its divisors is an integer number (5427408).

Almost surely, 2^21580241 is an apocalyptic number.

It is an amenable number.

21580241 is a deficient number, since it is larger than the sum of its proper divisors (129391).

21580241 is a wasteful number, since it uses less digits than its factorization.

21580241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129390.

The product of its (nonzero) digits is 640, while the sum is 23.

The square root of 21580241 is about 4645.4537991460. The cubic root of 21580241 is about 278.4103845229.

Adding to 21580241 its reverse (14208512), we get a palindrome (35788753).

The spelling of 21580241 in words is "twenty-one million, five hundred eighty thousand, two hundred forty-one".